Accessible animation and customizable graphics via simplicial configuration modeling

O ur goal is to em bed free-form constraints into a graphical m odel. W ith such constraints a graphic can m aintain its visual integrity— and break rules tastefully— while being m anipulated by a casualuser. A typicalparam eterized graphic does notm eet these needs because its configuration space contains nonsense im ages in m uch higher proportion than desirable im ages, and the casual user is apt to ruin the graphic on any attem pt to m odify oranim ate it. W e therefore m odel the sm all subset of a given graphic's configuration space that m aps to desirable im ages. In our solution, the basic building block is a sim plicial complex— the m ost practical data structure able to accom m odate the variety of topologies that can arise. The configuration-space m odel can be built from a cross productofsuch com plexes. W e describe how to define the m apping from this space to the im age space. W e show how to invert that m apping, allow ing the user to m anipulate the im age without understanding the structure of the configuration-space m odel. W e also show how to extend the m apping when the originalparam eterization contains hierarchy, coordinate transform ations,and other non linearities. O ur software im plem entation applies sim plicial configuration m odeling to 2D vector graphics.